Deyeron is the Elvish word given to the multicontinental region of the Known World, within which lie the kingdoms of Riverfall, Windspeak, Nightfall, and Yvaereth. The Forgotten Island and the Tower of Vyrohimn are also located within Deyeron.
Each continent on Deyeron has a different climate and landscape. Riverfall is covered by rolling hills and valleys, all grass-covered. Nightfall is more barren, with cliffs of black rock protruding from deserts of grey sand. The landscape of Windspeak is hidden by thick fog for most of the year, though beneath the shroud is something similar to Riverfall, with many rivers and vast mountain ranges. Yvaereth, a smaller kingdom that the rest, is beaten by sandstorms and unrelenting heat.
Between the continental kingdoms lie great expanses of ocean, under which lie deep-sea caverns and, according to some, monsters and spirits. The Dragon Islands connect Riverfall, Yvaereth, and Windspeak, and the travelling slave drivers known as the Yzerren patrol these islands, capturing travelers to bring back to Yvaereth.
Before being captured and populated by the humans, Deyeron was inhabited by elves - both Faynin and Eflan. After the Great Victory of the First Age, each continent was divided into kingdoms by the royal families, and the Faynin Elves were forced into their mountain halls to hide away from their oppressors. During the Second Age, wars were fought over territory, but the rules of each kingdom retained their thrones.
In The Plight of Steel, which takes place at the start of the Third Age, Aerynir Vaenoria, the Lord of Ashes and son of Shyrrik Vaenoria, the king who fought with Alvador Zorander, planned to start a war with the humans and take back Deyeron, which he believed his father too easily lost. He sent elvish emissaries to each of the kingdoms to try and manipulate the rulers and turn them against each other in an effort to incite a rout of in-fighting that would wipe out most of their forces. This plan mostly failed, as one of the three emissaries was ambushed by thieves on the road and killed. The second, Myrrin Elasor, joined with Elden Killian's party in Windspeak, effectively switching sides. The third, Alluin Lathlirel, did make it to Nightfall, proving to be the only one successful out of the three.
The humans of Deyeron are known to be intolerant of Faynin Elves due to the history of war between the two races. Aerynir's first emissary was likely killed due to his appearance, while Myrrin was attacked numerous times on the road to Starlight Palace, though this is not seen in the novel.
The name Deyeron is an elvish word, meaning Haven. Human settlers kept the name they heard from their vanquished enemies, though some more opinionated folk have also created other names for it, such as Overland, Seabrink, and, amusingly, Man's Conquest.